use python 3.9 for the sake of nose

Author: chfw

.github/workflows/tests.yml

@@ -11,7 +11,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [Ubuntu]
-        python_version: ["3.10.19"]
+        python_version: ["3.9.24"]
 
     steps:
       - uses: actions/checkout@v2